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ORH_wxman

Arctic Sea Ice Extent, Area, and Volume

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Late month update on area....how other years compare to 2017:

2016: -300k

2015: -190k

2014: +340k

2013: +50k

2012: -520k

2011: -330k

2010: -110k

2009: +410k

2008: +350k

2007: -320k

 

We are closest to 2013 right now, but when you look at the numbers, it doesn't necessarily that means where we will end up. You can see that 2008 still had pretty high area at this point (350k ahead of 2017 and 300k ahead of 2013), but much of it was vulnerable ice in the Laptev so it melted back quite a bit in August....whereas a year like 2013 had already melted out most of the vulnerable ice so it stalled and finished significantly higher than a year like 2008. The next closest year is 2010. I still think a finish close to 2010 is probably the most likely right now. That year finished at 3.07 million sq km for area....though really anything plus or minus 200k from that is fair game.

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3 hours ago, ORH_wxman said:

Late month update on area....how other years compare to 2017:

2016: -300k

2015: -190k

2014: +340k

2013: +50k

2012: -520k

2011: -330k

2010: -110k

2009: +410k

2008: +350k

2007: -320k

 

We are closest to 2013 right now, but when you look at the numbers, it doesn't necessarily that means where we will end up. You can see that 2008 still had pretty high area at this point (350k ahead of 2017 and 300k ahead of 2013), but much of it was vulnerable ice in the Laptev so it melted back quite a bit in August....whereas a year like 2013 had already melted out most of the vulnerable ice so it stalled and finished significantly higher than a year like 2008. The next closest year is 2010. I still think a finish close to 2010 is probably the most likely right now. That year finished at 3.07 million sq km for area....though really anything plus or minus 200k from that is fair game.

Just to make sure I understand, when it says -320K, for example, it means 2007 had 320K less than 2017, or the other way around?

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18 hours ago, WidreMann said:

Just to make sure I understand, when it says -320K, for example, it means 2007 had 320K less than 2017, or the other way around?

You're correct...you can use the other years as baselines....higher ice years like 2009 and 2014 are larger positive values.

 

 

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It will be interesting to see if the September 2012 low extent record can remain in place into the early 2020's. Or if the dipole pattern makes a return in 18-19 finally allowing a new record minimum to be set. Not sure many in September 2012 though it would take so long to break the record.

 

5980750b332f8_Screenshot2017-08-01at8_24_27AM.png.adcbd9d36777e6040f74dd97deace404.png

 

 

 

 

 

 

 

 

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25 minutes ago, J Paul Gordon said:

Will the bottoming out of solar irradiation due to decreased sunspot activity affect sea ice minima in the Arctic basin?

The effect is too small to really make a difference. Maybe only 0.3 watts per meter sq in high amplitude cases....which might be like a tenth of a degree Celsius, but most likely the impact is less. If we had an extended min for like a decade or longer, then it might be somewhat noticeable.

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Solar activity (Jan-Dec sunspots via SILSO) is actually correlated pretty strongly with sea ice extent on August 1 in the Arctic going by http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/ but I think it is because the Sun & AMO flipped phases at similar times, i.e. the sun has weakened fairly consistently since the big solar years in the 1930s-1990s, and the 70s/80s/early 90s is when the AMO was cool, now it is warm.

 

Arctic Sea Ice (Aug 1) v. Sunspots Jan-Dec.PNG

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PIOMAS updated for August 1st....2017 has now relinquished its place for lowest volume to 2012 for the first time this year...albeit still very close. I think it is unlikely 2017 will be able to match 2012's losses from here on out, but if the weather is bad enough, who knows for sure.

 

 

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3 hours ago, ORH_wxman said:

PIOMAS updated for August 1st....2017 has now relinquished its place for lowest volume to 2012 for the first time this year...albeit still very close. I think it is unlikely 2017 will be able to match 2012's losses from here on out, but if the weather is bad enough, who knows for sure.

 

 

Doesn't the weather look favorable with a vortex near Alaska/Beaufort?

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23 minutes ago, nzucker said:

Doesn't the weather look favorable with a vortex near Alaska/Beaufort?

Yeah the vortex is mostly hanging out over the CAB...there's a pretty strong storm in the couple days...we'll see if that is strong enough to do any damage. But it is definitely not the typical pattern for huge melting out shown through mid-month.

The biggest enemy of the ice is how thin it was at the beginning of the year. If this pattern happened in 2015, we probably would have seen a minimum extent in the mid 5s.

 

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It's easy to just focus on the recent melt seasons but I got a jolt when I looked at the PIOMAS sea ice volume plot.  The SIV is currently around 6.75K km3, just behind 2012 as ORH reported above, but the 1979-2001 average for this time of years is almost 17,000 km3, more 10,000 km3 greater than today - a loss I find sobering.

piomas-trnd4.png?attachauth=ANoY7cotCUzO

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I would trust the dynamical more than the statistical, because we are in uncharted territory here. Even so, it looks like the median of those models would still be above 2012.

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I don't understand why there is this belief in linear models.

Everything we know about climate and weather says jumps are the norm, not slow and gradual transitions from one state to another.

So why would we expect arctic ice to behave differently? Based on precedent, we should bump around a record low for a while .

Then, if the environment remains favorable, we jump to a zero late summer ice regime. The Viking records suggest as much.

The real question is whether this is a cyclical or a secular development. Does anyone have any substantive input towards answering this question?

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3 hours ago, etudiant said:

I don't understand why there is this belief in linear models.

Everything we know about climate and weather says jumps are the norm, not slow and gradual transitions from one state to another.

So why would we expect arctic ice to behave differently? Based on precedent, we should bump around a record low for a while .

Then, if the environment remains favorable, we jump to a zero late summer ice regime. The Viking records suggest as much.

The real question is whether this is a cyclical or a secular development. Does anyone have any substantive input towards answering this question?

There is a cyclical pattern on top of the underlying anthropogenic warming. The Arctic is kind of a tough one though because it has previously responded to global temperature changes much more rapidly than other regions...so we don't have a great idea on how it will behave with added anthropogenic warming. We do know that it warmed about 5x the rate of the rest of the globe in the early 20th century and cooled about 5x the rate during the cooling period 1940-1970...and recently it has warmed about 10x faster than the rest of the globe. There's probably been some natural warming helping out since the mid 90s when the AMO flipped on top of anthro warming. 

 

As for the ice, there was a paper that came out (Tietche et al) in 2011 that had looked at what happens when we approach an ice-free state and if it caused any "tipping point". It found that it did not...it actually found the opposite conclusion...which suggested as we get closer to ice free, it may take longer to get that final push than it did to go from 1990s levels to 2007 levels of ice. It showed that winter temps need to be about 2-3C warmer than currently (or maybe another 1-1.5c if you just use last winter's excessively warm temps) to consistently have a great chance to melt all the ice out in summer using model projected 2050 temps. Now, maybe this is too optimistic for the ice...it has shrunk faster than previous models said it would so we will have to see if that trend continues...or if the flattening happens. There's some recent argument for both cases...on the one hand, we have basically a flat trend in area/extent since 2007 and we've seen rebounds following record lows which follows the Tietche et al theory, but the volume trend is still downward too so will there some "flash melting" type event? Maybe...if we keep the volume trend down, then yeah it could happen pretty soon. But we've seen volume rebounds after records so of the same happens after this season, then it will probably push the ice-free date back another couple years. 

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8 hours ago, ORH_wxman said:

Yeah the vortex is mostly hanging out over the CAB...there's a pretty strong storm in the couple days...we'll see if that is strong enough to do any damage. But it is definitely not the typical pattern for huge melting out shown through mid-month.

The biggest enemy of the ice is how thin it was at the beginning of the year. If this pattern happened in 2015, we probably would have seen a minimum extent in the mid 5s.

 

There are windy conditions as the low bottoms out near 980mb but also a cold core of -10C 850s near the NE Beaufort as well as uniformly below freezing 850s across the Arctic to balance it out. The ECM/GFS take the deep vortex out towards August 15th, becomes difficult to see huge losses as we approach the second half of August. A lock now that area and extent finish above 2007 and 2012, probably 2011 as well. 

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14 hours ago, WidreMann said:

I would trust the dynamical more than the statistical, because we are in uncharted territory here. Even so, it looks like the median of those models would still be above 2012.

We missed our chance to beat 2012  when the strong dipole pattern of 2007-2012 failed to emerge in June. So the 2012 extent record will remain safe another year. The HadGem model did a great job back in 2012 showing a slower rate of loss vs the extreme 2005-2012 loss rate.

 

I am wondering if the dramatic dipole reversal following the historic 2007-2012 rapid melt seasons is a result of the weaker AMOC?

 

http://nsidc.org/arcticseaicenews/

In the far northern Atlantic, warm water flowing northward from the tropics is cooled by the atmosphere, becomes denser, and eventually sinks to great depths. The descending water is key in driving a sub-surface and surface ocean circulation system called the Atlantic Meridional Overturning Circulation (AMOC), which is part of the global ocean conveyor belt of heat and salinity. Where the Atlantic water sinks has a very important effect on the climate of Northern Europe; the heat that the ocean loses to the atmosphere is what keeps Northern Europe quite warm relative to its latitude. For example, Amsterdam is at the same latitude as Winnipeg, Canada, but experiences much warmer winters.

Based on a recent modeling study, Florian Sévellec and colleagues propose that the ongoing loss of Arctic sea ice may disrupt the AMOC. The sea ice loss leads to a freshening of the northern North Atlantic and stronger heat absorption at the surface. This means that waters in the northern North Atlantic are less dense than they used to be, which has the effect of providing a cap, or lid, that may inhibit the northward flow of warm waters at the surface and the eventual sinking of these waters. The authors suggest that the Arctic sea ice decline may help to explain observations suggesting that the AMOC may be slowing down, and why there is a regional minimum in warming (sometimes called the Warming Hole) over the subpolar North Atlantic.

 

 

 

500.png.82674e0b1e843e577080398d3db7d3f5.png

 

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51 minutes ago, bluewave said:

We missed our chance to beat 2012  when the strong dipole pattern of 2007-2012 failed to emerge in June. So the 2012 extent record will remain safe another year. The HadGem model did a great job back in 2012 showing a slower rate of loss vs the extreme 2005-2012 loss rate.

 

I am wondering if the dramatic dipole reversal following the historic 2007-2012 rapid melt seasons is a result of the weaker AMOC?

 

http://nsidc.org/arcticseaicenews/

In the far northern Atlantic, warm water flowing northward from the tropics is cooled by the atmosphere, becomes denser, and eventually sinks to great depths. The descending water is key in driving a sub-surface and surface ocean circulation system called the Atlantic Meridional Overturning Circulation (AMOC), which is part of the global ocean conveyor belt of heat and salinity. Where the Atlantic water sinks has a very important effect on the climate of Northern Europe; the heat that the ocean loses to the atmosphere is what keeps Northern Europe quite warm relative to its latitude. For example, Amsterdam is at the same latitude as Winnipeg, Canada, but experiences much warmer winters.

Based on a recent modeling study, Florian Sévellec and colleagues propose that the ongoing loss of Arctic sea ice may disrupt the AMOC. The sea ice loss leads to a freshening of the northern North Atlantic and stronger heat absorption at the surface. This means that waters in the northern North Atlantic are less dense than they used to be, which has the effect of providing a cap, or lid, that may inhibit the northward flow of warm waters at the surface and the eventual sinking of these waters. The authors suggest that the Arctic sea ice decline may help to explain observations suggesting that the AMOC may be slowing down, and why there is a regional minimum in warming (sometimes called the Warming Hole) over the subpolar North Atlantic.

 

 

 

 

 

The cold pool in the North Atlantic also really expanded and intensified in 2013 which was right after the huge Greenland melt in 2012...so I wonder if that was at least partially related. 

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12 minutes ago, ORH_wxman said:

The cold pool in the North Atlantic also really expanded and intensified in 2013 which was right after the huge Greenland melt in 2012...so I wonder if that was at least partially related. 

It could also be related to why the Siberian October snow signal hasn't worked in recent winters with the stronger PV and more +AO/+NAO.

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I'd thought the air temperature was not as significant as the water temperature in driving the amount of melting in the Arctic. Is this a misperception?

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1 hour ago, etudiant said:

I'd thought the air temperature was not as significant as the water temperature in driving the amount of melting in the Arctic. Is this a misperception?

Yes, in August most melting is from water below the ice. Of course colder air cools the water also. Last season saw strong late season melting due to storminess even though temperatures were cool.

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Recent cooler temps and stronger polar vortex let 2017 fall a little behind 2007 over the last few days.

 

5989e6dc8b816_Screenshot2017-08-08at12_25_14PM.png.9341d71ffaa7b8081452231bbd022766.png

 

sie_daily_for_selected_years.thumb.png.b100df478a3a8e4292f52137cb4e5401.png

 

 

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The AMO really does seem to have tremendous influence on the ice extent on Aug 1, or it is an amazing coincidence, I got an r-squared of 0.44 for annualized AMO to Aug 1 sea ice extent. The sun is a weak predictor of sea ice extent change for Aug 1 - Peak extent, but the AMO was still correlated at 0.22 r-squared. The AMO has been trending much lower than last year since June, so that coincides well with relatively little ice lost from the peak date (which varies) to Aug 1. Peak to Aug 1 losses are the lowest since 2006.

Sunspots & AMO, when annualized correlate at 0.06 for 1979-2016, so that's kind of weird in its own right.

The AMO seems to have been hot (>=0.2) on an annual basis 11 times in the prior warm cycle (~1926-1963), so would suspect we're almost done with these super warm years, there are probably two more shots in an AMO sense at breaking the 2012 record, assuming it doesn't happen in 2017, before 2020-2030 when the cold AMO sets in and slows/reverses the trend in declining ice. 

Super Warm Years (>=0.2) 1926-1963: 1932, 1933, 1937, 1938, 1944, 1945, 1951, 1952, 1953, 1958, 1960

Super Warm Years (>=0.2) since 1994: 1998, 2003, 2004, 2005, 2006, 2010, 2012, 2016, 2017* (probably)

The AMO years under -0.10 average 8.786 million km^2 sea ice extent on Aug 1, the AMO years over +0.10 average 7.397 million km^2 sea ice extent on Aug 1, so some kind of slow down seems possible even with the Earth is warmer in the 2020s, back to maybe the late 1990s / early 2000s level?

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There has traditionally been a relationship between Arctic sea ice and the AMO as we have seen with the decline in the 20's and 30's. More specifically, the region south of Greenland seems to have the largest influence on September minimum extent. When those SST's were at their warmest from 2005 -2012, there were three new records set in 2005, 2007, and 2012. The reversal to cooler SST's in this region since 2013 has been accompanied by no new September extent records. You can see the 2005-2012 rate of decline was in a class by itself with nothing else coming close. While that area south of Greenland has cooled dramatically in recent years, the AMO has still remained positive.

512.png.b0869eca6d43743aa5afffc116cd60ad.png

1317.png.d9c1ce65606f50dade93a5cd1861eb48.png

monthly_ice_09_NH-350x270.png.9098ca5e11ac63c0dec1767403f61bd8.png

 

 

 

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We have a pretty compact ice pack right now...area is running about 6th lowest but extent is flirting around the 3rd lowest mark right now only above 2007 and 2012 though on a few of the data sources it is a bit above 2016 as well. 

My guess is that we may see extent loss slow some at some point and area loss pick up a little more or at least pick up relative to extent loss. Most of the years with similar compactness right now saw some noticeable slowing of extent loss. 

We have a pretty strong storm right now in the Arctic and it is late enough in the season that perhaps it could do some damage. Kind of like the 2012 cyclone but less extreme since it is both weaker and the ice this year is not as in bad shape as 2012 was before that cyclone hit. We will see if it damages the ice enough to cause a late season cliff in extent loss. I'm probably leaning against anything huge though given the higher area right now...but you never know. If we form a potent dipole late in August that helps compact the ice more we could see big extent loss anyway like we saw in 2015 (that year ended on a huge extent cliff even while area loss was light) 

 

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